1. Field of Disclosure
Embodiments of the present invention generally relate to a backlight unit capable of stably driving a light source using a constant direct current voltage.
2. Description of the Related Art
Liquid crystal display (LCD) devices utilize liquid crystal molecules, which are non-light emitting elements, such that a backlight unit is required in order to produce light.
The backlight unit may include a plurality of light source arrays including a plurality of light emitting diodes (LEDs).
The backlight unit may be controlled by a dimming method so as to improve image quality. In the case of dimming control, a voltage level of a direct current (DC) voltage applied to the light source may be adjusted. In order to adjust a voltage level of a DC voltage, conventional backlight units may include a DC-DC converter for a backlight.
The DC-DC converter for the backlight may include an inductor, a switching element, a diode, and a capacitor.
Accordingly, conventional backlight units have a large volume due to the DC-DC converter.
Meanwhile, it is also possible to drive backlight units using a constant DC voltage without a DC-DC converter. In this case, however, the constant DC voltage may bring disadvantages as follows:
When a DC voltage applied to the light source is substantially large, a duty ratio of a driving current is required to be decreased considerably so as to keep a predetermined amount of the driving current. In this case, the light source may not be turned on, when the duty ratio is decreased below a certain value.
It is to be understood that this Related Art section is intended to provide useful background for understanding the technology and as such disclosed herein, the technology background section may include ideas, concepts or recognitions that were not part of what was known or appreciated by those skilled in the pertinent art prior to a corresponding effective filing date of subject matter disclosed herein.